Question in screen shot

If x=-3 is the only x-intercept of the graph of a quadratic equation, which statement best discribes the discriminant of the equation?

How do i start to solve? would appreciate a walk-thru! a bird sitting 16ft above the ground in an apple tree dislodges an apple. after how many seconds does the apple land on the ground? (assuming that no branches will interfere with it's fall)

Point b lies between points a and c on . let x represent the length of segment ab in inches. use the segment to complete the statements. the value of x is . the length of in inches is . the length of in inches is .